Trenching in rocky soils

ABSTRACT

A method and apparatus for the excavation of trenches, more especially for the subsequent construction of subterranean walls, diaphragms or bulkheads, of the type in which an excavating device is caused to advance along a main axis of excavation, comprising a guide of the said device, substantially perpendicular to the said main axis, on said guide being made to run at least one excavating tool in the form of a mandrel which can be rotated about an axis substantially parallel to the said main axis and which has cutting edges on its lateral surface, the said tool discharging the reactions caused by the action of excavation almost exclusively in the transverse direction to the main axis through the said guide and against one or other lateral wall of the excavation.

I United States Patent [1113,614,161

[72] Inventor (H Miotti 1,580,001 4/1926 Bicknell 175/91 Milan, Italy 3,314,725 4/1967 Tinlin 175/91 X {2]} A No. 850,365 3,459,452 8/1969 Schnabel.... 175/91 X [22] Filed Aug. 15, 1969 3,477,762 11/1969 Frenyo et al 299/10 [45] Patented Oct. 19, 1971 3,509,949 5/1970 Kukihara 17519] X [73] Assignee 1.C.D.S. Impresa Costruzionl Opere Primary Examiner EmeSt Purser I speciauuate Anomey-Beveridge & De Grandi Milan, Italy [32] Priority May 31, 1969 [33] Italy [31] 17626A/69 ABSTRACT: A method and apparatus for the excavation of [54] TRENCHING IN ROCKY son's trenches, more especially for the subsequent construction of 12 Claims snrawing Figs. subterranean walls, draphragms or bulkheads, of the type n whlch an excavating device 18 caused to advance along a mam U-S. .1 axi of excavation comprising a guide of the aid device ub- 37/80 37/ 1.75/9, 299/40 stantially perpendicular to the said main axis, on said guide [51] Int. Cl. E21c 37/00 being made to run at 1635 one excavating too] in the f f [50] Field of Search 299/10, 18, mandrel which can be rotated about an axis substantially 40; 37/80 195; 5" parallel to the said main axis and which has cutting edges on its lateral surface, the said tool discharging the reactions [56] Reterences cued caused by the action of excavation almost exclusively in the UNITED STATES PATENTS transverse direction to the main axis through the said guide Re. 14,454 4/1918 Dean 175/91 X and against one or other lateral wall of the excavation.

namcnmo m nocxv sorLs BACKGROUND OF THE INVENTION According to one known technique, the method of excavation is effected by first making a series of holes at intervals, each of which is separately filled with concrete; the next stage is to make a second series of holes between each of the first holes, at a tangent to or completely intersecting these latter, and these holes are also filled with concrete so as to form substantially a continuous wall with the first holes.

A different technique is to make, instead, a complete series of adjacent holes until these form a single extended excavation, which can then be filled with concrete in one operation to fonn a continuous wall.

Either system permits the use of different types of excavation means, in accordance with the consistency of the ground which has to be excavated. In comparatively friable soils, a socalled biting grab is generally used; under the weight of the grab itself and of a ballast connected to the grab, the cutting edges of the latter are made to engage firmly into the ground with force andwhen the two valves of the grab are closedmake an excavation. The material excavated is automatically picked up inside the grab when it is closed, and can thus be easily brought to the surface.

In the case of rocky terrains, on the other hand, a chiselling tool is generally employed; this can have either a rotating or a striking movement. In connection with the chisel, means for removing the excavated material are also necessary, whichwhen working in the presence of bentonite mud, as already mentioned-can be formed in a simple manner from suction pipes.

The chisel can be employed either to make a series of holes which are vertical, successive and adjacent, and are in the collective form of one extended excavation, in the form of a trench, or to make an immediate extended excavation, in which case the chisel can also havein addition to a rotating or striking movementa movement of translation along the excavation. Although the chisel is very effective on hard ground, it is obvious that its method of operation is very slow.

Finally, when the ground is of medium consistency or of heterogeneous character, the grab can be used in conjunction with the chisel; in such a case the chisel is first employed to make the excavation of several vertical holes at appropriate intervals, ad the material remaining between the said holes is then removed by means of the biting grab.

In all the types of excavating tools previously described, the tool reacts-when the action of excavation is directly from top to bottom-by a thrust from the bottom upwards. In order to oppose this thrust the excavating tool is generally well ballasted, so that it is frequently cumbersome and difficult to handle, and furthermore the use of it entails an external support compartmentation which is particularly resistant.

In an attempt to obviate this disadvantage, there has already been proposed a tool structure in which an oscillating ladle for excavation can be moved along a horizontal guide, which is laterally attached to the walls of the excavation. This system has been found to permit the work to be done more accurately, but the opposition of the guide on the walls of the excavation is generally insufficient of itself to sustain the direct upward reaction of the tool. This is particularly noticeable in ground of a mixed character, when the excavating tool-on unexpectedly encountering areas of ground which is of higher consistencyreacts with a noticeable upward thrust. The apparatus then also requires ballasting,.although generally to a lesser extent.

SUMMARY OF THE INVENTION All these disadvantages are eliminated by the method, as well as the apparatus according to the invention, which permits the use of means which are less cumbersome, less heavy and thus easier to handle, either in regard to the apparatus proper, and to the external equipment. Such a method is in fact characterized in that, upon a guide which is substantially horizontal and corresponds in length to a defined extent of excavation, an excavating device is made to run, which rotates round a vertical axis and is provided with cutting edges on its lateral surfaces, which discharges the reaction caused by the action of excavation almost entirely in the horizontal direction. As will be easily understood, such a method no longer entails the ballasting of the apparatus, nor yet a transverse blocking of it against the walls of the excavation; in fact, when the device is propelled towards one end of the excavation, the guide of the device can rest firmly against the opposite end of the excavation, and conversely when the device is operated in the opposite direction, taking into account that small transverse displacements, caused by the force of the excavated material on the mandrel or cutting blade, have in practice no effect on the accurate operation of the device.

According to the present invention, a device which permits the simple operation of the method described above is further characterized in that it comprises a guide means which is adapted to be suspended in conformity with the excavation, a first carriage which can glide on the said support and is provided with means of attachment to the support itself, a second carriage which can glide in relation to the first and provided in turn with means of attachment to the support, and a mandrel or cutting blade which can be rotated, having a substantially vertical axis, provided with cutting edges on its lateral surfaces and carried by one of the said carriages.

According to a preferred form of embodiment, the axis of the said mandrel is inclined by approximately 5 in relation to the vertical in the direction of advance of the carriages during the excavation.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is, however, better described in more detail with reference to a preferred embodiment of the device, given however solely by way of an example and without any limitative effect, and illustrated in the attached drawings, in which:

FIG. 1 is a complete diagrammatic view of the device, at the start of an excavation operation;

FIG. 2 is a front view, in partial section, of the sole group of slides of the device; of trenches FIG. 3 is a diagrammatic sectional view, according to the line Ill-Ill in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT As is illustrated, the device comprises a support means or bench or guide support 1, which is lowered into the excavation by means of pulleys 2.

The bench 1 has a pair of longitudinal rectilinear guide means 3, and a series of transverse holes 4 at regular intervals, in parallel alignment to the guide 3.

A first carriage or positioning slide can slide along the guides 3, and a second 6 or control slide can run on this first slide. As is more clearly shown in FIGS. 2 and 3, the slide 5 is provided with a pair of raised elements 5', which act as sliding runners inside the guides 3, opposite; these runners 5' have preferably a swallow-tail profile, and at the same time act as running elements and support elements for the slide 5.

The slide 5 is substantially formed like a big gantry attached to the vertical legs 5" whereof is a pair of horizontal shafts 7, on which the slide 6 is mounted to be slidable. The shafts 7 each have a diaphragm means 8, which is adapted to act as a piston inside the cylindrical chambers 9 provided in the slide 6. With this arrangement, when fluid is sent under pressure inside the chambers 9, from one side of the diaphragm 8 or from the other, the resulting reaction is to move the slide 6 on the shafts 7.

A shaft 10 which carries the mandrel or cutting blade and which is free to rotate, but cannot slide axially, is mounted on the slide 6. Fastened to the lower end of the shaft 10 is a working head 11, provided with a set of tools 12 of a type known per se, mounted so that they can be interchangeable.

Fastened to the upper end of the shaft 10 is a gear 13, through which a rotation is imparted to the shaft 10 itself. The gear 13 engages with the gear 14 (or with a set of reducing gears) contained inside the tin box 15 and driven by a hydraulic motor 16.

As mentioned, the shaft 10 can rotate on the slide 6 on which it is mounted for example by means of a sleeve or bearing 17; this hearing is formed so as to prevent any axial sliding.

The sleeve 17 is in turn mounted to rotate on a pivot means 18, which allows the shaft 10 to oscillate briefly. This movement is such as will allow the shaft 10 to be accurately arranged-with an inclination of approximately in relation to the vertical and towards the direction of advance of the excavation operation (the direction shown by the arrow F in the arrangement according to FIG. 2)-whenever the device reverses its working course.

Finally, the head 11 and the said shaft are perforated axially and the hole accords on the upper side with the suction duct C.

Associated with the slide 5 is a pin 19 which can be moved transversely and similarly associated with the slide 6 is a pin 20. The pin 20,-as likewise the pin l9-can be actuated by means of a hydraulic jack to an insertable position in which the pin 20 projects from the profile of the slide 5, or to a retractable position in which the pin is withdrawn in relation to the said profile.

The pins 19 and 20 are arranged on an alignment whichwhen the device is assembled-is parallel to the alignment of the holes 4. When the pins 19 and 20 are in the insertable position, they lock within the holes 4. The horizontal distance between the pins 19 and 20-either in the position of commencement of travel of the slide 6 or in the position of end of travel-is equal to a whole multiple of the distance between two consecutive holes 4.

The method of operation is as follows: assuming that an excavation as defined by the two lines S -S, is to be carried out, the first step is to make a preliminary vertical hole in the ground, bounded on one side by the said line S, and on the other by a line 8;, and having a diameter which corresponds substantially to the maximum diameter of the mandrel 1 1. The device is lowered onto the ground engaging the mandrel 11 in the said preliminary hole, and the mandrel 11 itself is then made to rotate.

At the beginning of the operation the pin 19 of the slide 5 is engaged in a hole 4, whereas the pin 20 is in the position of rest. The pressurized inflow of fluid is then directed by pressure generating means into the chamber 9, so as to cause the slide 6 to move in the direction of operation. As the slide 6 gradually moves forward together with the mandrel 11, the latter makes the excavation with a grinding action, whose reaction is direct-as will be easily understood-in a direction which is substantially horizontal.

When the slide 6 has completed its travel, the pin 20 finds itself exactly in correspondence with a hole 4; thus then pin 20 is moved by a pin moving means so that it engages in the said hole 4, thus blocking the slide 6 on the support 1. At the same time, the pin 19 is retracted by a pin moving means.

The slide 6 remaining blocked on the support 1, the fluid in the chamber 9 is then moved by pressure generating means in the direction corresponding to a return travel of the slide 6. Since the latter is stationary, the slide 5 reacts with a forward movement; at the end of travel, the pin 19 lies once more in front of a hole 4 and can then be inserted in order to block the slide 5 again on the support 1. The pin 20 is then brought back to the retracted position and the slide 6 can recommence a work cycle together with the mandrel 1 1.

Throughout the time that the mandrel 11 is operating, the pipe C maintains a suction to remove all the broken material together with the bentonite mud. The latter is then separated and recycled, in a substantially known manner.

When the mandrel 11 has reached the end of a complete course, i.e. after having made the excavation up to the line 8,, the slide complex is rapidly brought back to the rear as far as the line 8,, the support 1 is lowered by a height corresponding to the height of the excavation effected and the mandrel 11, which is again lodged in the preliminary hole S,-S,, can commence a fresh stage of excavation, and so on to the depth desired.

Although the system described above illustrates the correct method of procedure, it has nevertheless been found that it is also possible to dispense with the preliminary hole-more especially on ground of slight or medium hardness. In this case the head 11 is preferably provided with cutting edges also on its frontal surface; the support 1-with the mandrel group projecting from its lower profile l'can then be simply rested on the ground. As soon as the mandrel starts to rotate, being aided by the mere weight of the device, a short vertical hole is first excavated; when the edge 1' of the support 1 is supported correctly and fully, the forward travel of the mandrel can then be commenced for the operation of excavation proper; and so on in the following stages of the excavation. In this case, it then becomes unnecessary for the device to make an idle return travel subsequent to each course of excavation, but each forward and backward course of the device becomes, instead, a working course. Furthermore, in view of this it will then be generally appropriate for the mandrel to be able to reverse its direction of rotation.

The method and the device described above have many important practical advantages, both in regard to use as well as to the result of the completed work. of these, it seems fitting to mention at least the following:

1. Greater precision and speed in excavation;

2. Greater manageability, more especially due to the considerable reduction in the total weight. That the ballasting of the device can be abandoned is essentially due to the fact that--as mentioned above-the reactions of the excavation operation are almost entirely discharged in the horizontal direction against the walls of the excavation themselves;

3. Possibility of more exact control of the work states, and therefore of a fuller benefit from the capacity of the device. Actually, both the forward drive of the slides 5, 6 as well as the rotational drive of the shaft 10 are effected by hydraulic means, originating from a central unit outside the excavation; in that case this central unit has means for signalling the working conditions-cg. simply in the form of manometers for indicating the pressures of the driving fluids-from which the type of ground encountered at each moment by the mandrel can be inferred. In practice, if low working pressures are observed, it can be inferred that the device is encountering comparatively friable soil and the forward speed of the slide 6 can thus be increased; on the other hand, an opposite procedure may be observed when the device encounters banks of solid rock and an increase in working pressure is consequently indicated;

4. Possibility of almost complete automation of all the working stages by electric or electronic means of control and drive. The device according to the present invention acts in practice exactly like most modern machine tools, and as such it can be easily controlled by means of a completely automated operating program by using the said means for signalling and controlling the working conditions. It must, however, be understood that the invention is not limited to the embodiment described, but that this permits of very many variants, without thereby exceeding the scope of the said invention.

I claim:

1. An apparatus for the excavation of trenches having a depth in a first direction, comprising,

a rotatable cutting tool having cutting edges located on its lateral surfaces for abrading material to be excavated,

means for rotating said cutting tool about an axis substantially parallel to said first direction and for simultaneously advancing said cutting tool in a direction perpendicular to said first direction, whereby said cutting tool simultaneously rotates and advances in the earth thereby excavating a trench having a depth in said first direction and a length in said direction perpendicular to said first direction and whereby the reaction of the excavated material against the cutting tool is in said direction perpendicular to said first direction.

2. Apparatus according to claim 1 wherein said cutting tool is rotated about an axis which is inclined approximately 5 from said first direction.

3. Apparatus according to claim 1 further including a support means for said cutting tool movable in said first direction and having guide means located thereon extending in said direction perpendicular to said first direction, said cutting tool being movably attached to said guide means for movement in said direction perpendicular to said first direction.

4. Apparatus according to claim 3 wherein a first carriage is movably attached to said guide means for movement in said direction perpendicular to said first direction and a second carriage is movably attached to said first carriage for movement in said direction perpendicular to said first direction and wherein said cutting tool is fixedly attached to said second carriage.

5. Apparatus according to claim 4 wherein said second carriage is movably attached to guide means located on said first carriage extending in said direction perpendicular to said first direction and is caused to more on said guide means by pressure responsive diaphragm means located on said guide means located on said first carriage.

6. Apparatus according to claim 5 wherein said support means has a series of holes therein, situated in a straight line and lying parallel to said guide means located on said support means, and wherein each of said first and second carriage has associated with it a pin means movable between insertable and retractable positions and adapted to fit into and lock in any of said holes when in said insertable position.

7. Apparatus according to claim 6 further including pressure generating means for generating pressure in a direction which causes said pressure responsive diaphragm means to move said second carriage on said guide means located on said first carriage, in a given direction,

means for moving the pin means associated with said second carriage to said insertable position when said second car- .riage has traveled a predetermined distance,

means for moving the pin means associated with said first carriage to said retractable position when said second carriage has traveled said predetermined distance,

and pressure generating means for generating pressure after said second carriage has traveled said predetermined distance in a direction which would cause said pressure responsive diaphragm means to move said second carriage in a direction opposite to said given direction if said pin means associated with said second carriage were not in the insertable position, but which because said pin means is in said insertable position moves said first carriage in said given direction, whereby said first and second carriages are alternately moved in said given direction.

8. Apparatus according to claim 7 wherein said pin means are positioned on said first and second carriages so that when said second carriage has traveled said predetermined distance said pin means are located apart from each other a distance equal to a whole multiple of the distance between two consecutive holes in said support means.

9. Apparatus according to claim 8 wherein said cutting tool is mounted on a said second carriage by pivot means.

10. Apparatus according to claim 8 wherein said cutting tool is located on a hollow shaft which communicates with a suction means to evacuate the material which has been excavated.

l l. A method for the excavation of trenches comprising the steps of,

drilling a preliminary hole in the material to be excavated in a first direction, inserting in said preliminary hole a cutting tool having cutting edges on its lateral surfaces for abrading the material to be excavated, rotating said cutting tool about an axis substantially parallel to said first direction and simultaneously advancing said cutting tool in a direction perpendicular to said first direction whereby a trench is excavated having a depth in said first direction and a length in said direction perpendicular to said first direction and whereby the reaction of the excavated material against the cutting tool is in said direction perpendicular to said first direction. 12. The method of claim 11 wherein said axis is inclined at an angle of approximately 5' said first direction.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,614,161 Dated October 19 1971 Inventor-( Giosuk It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet [73] in the name of the Assignees, "I.C.D.S." should read I.C.O.S.

Signed and sealed this 7th day of November 1972.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. An apparatus for the excavation of trenches having a depth in a first direction, comprising, a rotatable cutting tool having cutting edges located on its lateral surfaces for abrading material to be excavated, means for rotating said cutting tool about an axis substantially parallel to said first direction and for simultaneously advancing said cutting tool in a direction perpendicular to said first direction, whereby said cutting tool simultaneously rotates and advances in the earth thereby excavating a trench having a depth in said first direction and a length in said direction perpendicular to said first direction and whereby the reaction of the excavated material against the cutting tool is in said direction perpendicular to said first direction.
 2. Apparatus according to claim 1 wherein said cutting tool is rotated about an axis which is inclined approximately 5* from said first direction.
 3. Apparatus according to claim 1 further including a support means for said cutting tool movable in said first direction and having guide means located thereon extending in said direction perpendicular to said first direction, said cutting tool being movably attached to said guide means for movement in said direction perpendicular to said first direction.
 4. Apparatus according to claim 3 wherein a first carriage is movably attached to said guide means for movement in said direction perpendicular to said first direction and a second carriage is movably attached to said first carriage for movement in said direction perpendicular to said first direction and wherein said cutting tool is fixedly attached to said second carriage.
 5. Apparatus according to claim 4 wherein said second carriage is movably attached to guide means located on said first carriage extending in said direction perpendicular to said first direction and is caused to more on said guide means by pressure responsive diaphragm means located on said guide means located on said first carriage.
 6. Apparatus acCording to claim 5 wherein said support means has a series of holes therein, situated in a straight line and lying parallel to said guide means located on said support means, and wherein each of said first and second carriage has associated with it a pin means movable between insertable and retractable positions and adapted to fit into and lock in any of said holes when in said insertable position.
 7. Apparatus according to claim 6 further including pressure generating means for generating pressure in a direction which causes said pressure responsive diaphragm means to move said second carriage on said guide means located on said first carriage, in a given direction, means for moving the pin means associated with said second carriage to said insertable position when said second carriage has traveled a predetermined distance, means for moving the pin means associated with said first carriage to said retractable position when said second carriage has traveled said predetermined distance, and pressure generating means for generating pressure after said second carriage has traveled said predetermined distance in a direction which would cause said pressure responsive diaphragm means to move said second carriage in a direction opposite to said given direction if said pin means associated with said second carriage were not in the insertable position, but which because said pin means is in said insertable position moves said first carriage in said given direction, whereby said first and second carriages are alternately moved in said given direction.
 8. Apparatus according to claim 7 wherein said pin means are positioned on said first and second carriages so that when said second carriage has traveled said predetermined distance said pin means are located apart from each other a distance equal to a whole multiple of the distance between two consecutive holes in said support means.
 9. Apparatus according to claim 8 wherein said cutting tool is mounted on a said second carriage by pivot means.
 10. Apparatus according to claim 8 wherein said cutting tool is located on a hollow shaft which communicates with a suction means to evacuate the material which has been excavated.
 11. A method for the excavation of trenches comprising the steps of, drilling a preliminary hole in the material to be excavated in a first direction, inserting in said preliminary hole a cutting tool having cutting edges on its lateral surfaces for abrading the material to be excavated, rotating said cutting tool about an axis substantially parallel to said first direction and simultaneously advancing said cutting tool in a direction perpendicular to said first direction whereby a trench is excavated having a depth in said first direction and a length in said direction perpendicular to said first direction and whereby the reaction of the excavated material against the cutting tool is in said direction perpendicular to said first direction.
 12. The method of claim 11 wherein said axis is inclined at an angle of approximately 5* said first direction. 